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Soooo, I have a s2 rb25 in a stagea. Power FC, splitfires, z32 afm, td06, nismo 550cc injectors, gtr fuel, tuned at 18psi.

Has been running fine for 6 months until yesterday it has developed a misfire under load and full boost. Seems ok at very light load and cruising.

Has constant miss when you stand on it and try and rev it out, also get a lot of black smoke out back.

Knock doesn't go above 18 with this happening.

I checked injector value in pfc and it got up to 90% just once, normally around 68-70% WOT. AFM voltage with car off is 0.42v according to the power fc and 1.72v at cruise approx.

I took plugs out (bpr7es gapped at 0.7), and swapped with some other spares I had laying around (not new but known working) and made very little difference.

I sprayed all the vac lines and hose clamps with brake cleaner but no change in idle speed. I did find 1 loose hose clamp after the turbo outlet under the air filter, but after tightening that, no change has been observed.

It was dark when I got into changing the plugs so I couldn't inspect the coil packs thoroughly. Might get around to it on the weekend.

Any suggestions.

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Cleaned afm, no change. Pulled coil pack leads 1 by 1 and idle got rough with each one. Seems to be when you get close to building boost it starts and then sputters then entire time on boost. Idles like normal, doesn't stall or dive.

That ain't going to help.

Tps voltage is 0.44v at idle. Check power to all coil pack plugs (14.19v across all 6). Unplugged afm and car died straight away.

I'm a bit stuck as to where I should check next? I went to repco and they didn't have any bcpr6es or bcpr7es on the shelf. I would have to order out of adelaide. I'm located alice springs so I can't just duck into a workshop with a dyno and it's my daily so I really wanna get this sorted

New plugs are in but only gapped at 0.8. Hesitates still coming onto boost but then clears up and revs clean through to redline. Makes the same amount of boost as normal once it gets up and goes. would pulling the gap back further make much of a difference that early in the Rev range if it clears up and revs clean after about 7psi?

Idles perfectly, and drives off boost as it did beforehand.

Also checked timing, 20deg btdc cold and fuel filter is new.

Hasn't got any leaks that I can see, no smoke from and where when it's running.

Edited by fmlycar

Just ask an R31 owner.

543.JPG

I don't understand. What is this. Will it fit in my RB30? just looking for a bit more power from my completely standard auto NA 1985 R31 that has 385,000 on the clock. Want to spend as little as possible thanx.

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